My DD was born 9 weeks early in Dec and it's a horrible expreience so really feel for your friend. She is going to need all the support she can get.
I am so glad that I expressed for the nine weeks it took for babyrascal to start feeding properly. We are now 18 weeks down the line and she is doing well and gaining weight nicely.
From a practical point of view she really needs to keep her strength up. As her friend the best thing you can do is make her evening meals, lasagne, cottage pie, casseroles, stews etc so when she gets in at night she has a healthy meal ready to warm up rather than cooking from scratch. Taking sandwiches to the hospital is great to. It's essential that she keeps her strength up.
Re Expressing she needs to be expressing at least 8-10 times in 24hrs including at least once through the night - a real bind but essential for getting and maintaining a good supply. However if she misses a session or two it's better not to stress just express asap.
She should be double pumping (ie both breasts each time) with a hospital grade pump.
Having a picture of baby when she is expressing helps the milk flow or even better at the side of the incubator. The unit should provide screens for privacy.
Once she can hold baby skin to skin contact is really good at improving supply.
She needs to ask someone to show her how to do hand expressing. She can then stimulate her breasts manually to help the let down before using the pump.
Oats are good for increasing milk supply.
Neonatal nurses (unfortunately) are not always the best supporters of breastfeeding. I had a lot of help from the hospital Breast feeding co-ordinator and this proved invaluable advice and support.
To ensure that Breastfeeding is established well she shoudl avoid using bottles and dummies for at least 6-8 weeks after baby has been feeding from the breast. In the meantime when baby is well enough and string enough she can cup feed baby rather than using bottles which can interfer with breastfeeding.
She needs someone to support her with her decision to breastfeed as she will undoubtedly come across people (Dr's and nurses) who will try to force the issue of using formula.
Think that's it for now! Sending big hugs to your friend. The NICU expereince isn't something that I would wish on my worst enemy it is a rtuely draining experience BUT she will get through it.